N.Y. Giants rookie TJ Moore made the play of his short NFL life Thursday night ... only to suffer a devastating leg injury minutes later, so gruesome the cornerback had to be carted off the field.

It happened in the fourth quarter of Big Blue's preseason finale against the New England Patriots at MetLife Stadium in New Jersey, when Moore was running down the field on kickoff coverage.

Moore's leg, after he planted it awkwardly, buckled ... bending in a very unnatural way.

TJ immediately grabbed his leg in serious pain, and his teammates surrounded him as Giants' quarterbacks Russell Wilson , Jameis Winston , and Jaxson Dart helped trainers carry him to the cart.

The unfortunate injury happened after Moore -- who the NYG signed after a rookie minicamp tryout -- secured a pick-si

See Full Page